324 INSECT LIFE. 



that the insect described is a butterfly, for the includ- 

 ing of characteristics that are true of all butterflies 

 would be unnecessary, and tend to obscure the im- 

 portance of the more distinctive features of the species 

 described. He should not attempt to say everything 

 possible about the insect, but should try to discover 

 and state in what respects the butterfly described 

 differs from other butterflies ; so that the reader of 

 his description can recognize with as little effort as 

 possible the particular species described. 



No detailed rules for describing insects can be 

 easily given ; the peculiar characteristics will be 

 found in different organs in different cases. The 

 following are some of the features that should be 

 studied in search for distinguishing characteristics 

 when describing adult insects : — 



1. The body as a whole. — The size of the insect; the general 

 color ; the color of the more prominent markings ; the relative pro- 

 portions of the head, thorax, and abdomen ; the clothing of the 

 body, as scales, hairs, and spines ; and any striking peculiarity of 

 the appendages of the body. 



2. The head.— The relative size of the head ; the details of the 

 color markings of the head ; the size and shape of the compound 

 eyes ; variations in size of the ocelli in different parts of the com- 

 pound eyes ; the presence or absence of hairs either in or fringing 

 the compound eyes; the number and position of the simple eyes; 

 the insertion of the antennas ; the general form of the antennae ; the 

 clothing of the antennae ; the relative length of the different seg- 

 ments of the antennae ; the form of the labrum ; the shape of the 

 mandibles ; the structure of the maxillae and maxillary palpi ; and 

 the structure of the labium and labial palpi. 



3. The thorax. — Peculiarities in the size and form of the thorax ; 

 the details of the markings of the thorax ; the structure and color- 

 ing of the wings ; the structure, clothing, and armature of the legs ; 

 and the position of the thoracic spiracles. 



